Project Summary Humberto Parada Jr, PhD, is tenure-track Assistant Professor of Epidemiology at San Diego State University (SDSU) and Associate Member of the University of California, San Diego (UCSD) Moores Cancer Center. Dr. Parada received his Ph.D. in epidemiology from the University of North Carolina at Chapel Hill (UNC) in 2016. As a cancer epidemiologist, Dr. Parada?s research goals are to identify environmental, behavioral (including dietary), and genetic factors that influence the development and progression of breast cancer, the most frequently diagnosed cancer and the second leading cause of cancer-related death among women in the United States (US), in order to refine risk reduction strategies to reduce the burden of breast cancer nationally and internationally. His proposal entitled ?Red Blood Cell Polyunsaturated Fatty Acids and Breast Cancer Mortality in the Women?s Healthy Eating and Living (WHEL) Study? seeks to investigate, using structural models, the associations between four ?-3 and four ?-6 polyunsaturated fatty acids measured in red blood cells (RBC) and mortality following breast cancer and gene expression in breast tumor samples. To date, the few epidemiologic studies that have examined fatty acids and breast cancer mortality have relied on self- reported assessments, which are subject to measurement error. The use of a biomarker measure together with novel analytical methods will allow Dr. Parada to objectively and more accurately estimate the associations between these eight polyunsaturated fatty acids and breast cancer mortality. Furthermore, while laboratory studies using breast cancer cells and animal studies have identified important mechanisms by which fatty acids may impact carcinogenesis and progression, no studies have examined fatty acids relative to gene expression in breast tumor samples. Documenting the associations between RBC fatty acids and breast cancer mortality would help to inform dietary intake guidelines among women diagnosed with breast cancer. The proposed career development and training plan includes three training goals to enhance Dr. Parada?s trajectory toward becoming an independent investigator: 1) Obtain training in nutrition science and nutrition-related cancer research, 2) Develop expertise in technical, analytic and conceptual approaches for biomarkers, and 3) Improve skills in grantsmanship and participate in career development opportunities. This project will be carried out at SDSU and UCSD under the guidance of his mentoring team with expertise in breast cancer epidemiology (Primary mentor: M. Elena Martinez, PhD), diet/nutrition (Co-mentor: Cheryl L. Rock, PhD, RD), environmental health (Co-mentor: Eunha Hoh, PhD), molecular epidemiology (Co-mentor: Melissa A. Troester, PhD), and biostatistics (Collaborator: Mingan Yang, PhD).